Milo g



Patented Oct. ,26, 1897.

M. G. KBLLQGG. MULTIPLE SWITGHBARD.

l/l//l//l (No Model.)

UNITED STATES PATENT i EEICE.

MILO e. kELLOee, OE CHICAGO, ILLINOIS, AssIeNOR rro TIIE IIELLOGC.swITCIIBOARD AND SUPPLY COMPANY, OE sAME PLACE.

MULTIPLE SWITCHBOARD.

SPECIFICATION forming' part of Letters Ifatent No. 592,342, datedOctober 26, 189'?. Application filed December 21, 1889. Serial No.334,520. (No model.)

To @ZZ whom t may concern.-

Be it known that I, MILO G. KELLOGG, of Chicago, in the county of Cookand State of Illinois, temporarily residing at Stuttgart, in the Empireof Germany, have invented certain new and useful Improvements inMultiple Switchboards for Telephone-Exchanges, of which the following isa clear, full, concise, and exact description, reference being had tothe accompanyingV drawings, forming a part of this specification.

My invention relates to telephone-exchange systems in which the linesare single-circuit lines or metallic-circuit lines, or in which the twolines are combined in one exchange; and it consists in a system ofswitching, calling, and testing with such lines which I shall describeand claim.

I place as many boards in the central ofiice as are found necessary ordesirable in order to properly answer the calls and make the necessaryconnections and disconnections. On each board is a spring-jack orsimilar switch for each line. Each switch has a contact-spring whichnormally bears on an insulated contact-point and has a contact-pieceinsulated from the rest (except by the circuit connections) and isadapted to receive a loop-switch plug and, when a plug is inserted, todisconnect the spring from the contact-point and connect the twocontact-pieces of the plug with the spring and with said switchcontact-piece, respectively.

The lines of the exchange, whether single or metallic circuit lines,pass successively through the pairsof contact-points of their switcheson the several boards. The lines then unite into a common wire in whichis a rheotome. W'hen the lines are switched for conversation, they aredisconnected from this common wire. Test receiving instruments at eachboard are connected to the other side of the rheotome and are adapted tobe brought for testing into connection with the several lines whetherthe lines are switched or not. The test receiving instruments and therheotome and its common wire are disconnected from the ground at thecentral oiice.

In the accompanying drawings, illustrating my invention, Figures l andlb represent sections of two multiple switchboards of the exchange towhich the same lines are Connected. Fig. 2 shows a diagram of the boardswith the line connections and apparatus necessary to illustrate myinvention. Fig. 8 shows an operator-s cord system to be used with theboards. Fig. 4C shows a subscribcrsstation apparatus. y

In the drawings like parts and apparatus are indicated by the sameletters and iigures of reference.

In Fig. 2, A is a sectional View of the switchboard shown in Fig. l, andA is a sectional view of the switchboard shown in Fig. 1b, each asindicated by the line CZ c.'

In Fig. 2, g g represent the springs of the switches, h h thecontact-points on which the springs normally bear, and j j the insulatedcontact-pieces of the switches. Z Z are the switch-holes. a b are therubber strips on which the contact-pieces are mounted, as shown, andthrough the fronts of which are the holes Z L.

The insulated contact pieces j j of the switches are so placed that atest-plug or similar device may readily be applied to them. When aswitch-plug (shown in Fig. 3) is inserted into a switch-hole Z, itseparates the pieces g h of the switch, and one of the contact-pieces ofthe plug is in contact with the piecej and the other piece is in contactwith the spring g.

The switches for the single-circuit lines are marked S and those for themetallic-circuit lines are marked S.

R is a rheotome or mechanical circuitbreaker containing aclocl\vorlmovement actuated by a spring. It contains an oscillating barfixed to the verge-shaft and standing at right angles to it. A pair ofcontactpoints is connected with the bar or with the shaft in such a waythat their contact is alternately made and broken with the oscillations.The pair of contact-points are properly insulated and are connected intothe circuit, as indicated for the rheotome.

Instead of the rheotome shown any form of mechanical or electricalrheotome or any ap` cated for the rheotome.

w and are calling-annunciators, one for each of the linesshown. Twolines are shown in Fig. 2, one a metallic-circuit line, the two sides orbranches of which are marked line No. l and line No. lb, respectively,and one a single-circuit line (to be grounded at its outer end) markedline No. 2.

The circuit of the single-circuit line is as follows: from thesubscribers ground throughv his station apparatus, throughv the line andthe pairs of contact-points g h successively of its switches on theseveral boards, going in each case to the point h rst, thence throughits line-annunciator to the common wire of the lines in which is therheotome. All the contact-pieces jj of a single-circuitv line areconnected together and to their line between its switches and thesubscribers station.

The circuit of a metallic-circuit line is as follows: One side or branchof the line-say line No. l, as shown-is connected with all thecontact-pieces j j of its switches on the boards. The other branch ofthe line-say line No. lb-vpasses successively through the pairs ofcontact-points g h of its switches on the several boards, going in eachcase to the spring first. It then passes through the lineannunciator andthence to the common wire in which is the rheotome.

t t are test receiving instruments, one at eachboard.Thesetestreceivinginstruments are preferably magneto-telephones, asshown, as they are peculiarly sensitive to variation of current on theline, and thus Well adapted to coperate with rheotomes even though therheotomes are shunted by complete circuits. It is obvious, however, thatany other kind of a test receiving instrument that will indicate willproperly cooperate with this system.

T T are test-plugs, one for each instrument, each connected by aiiexible cord to one side of its instrument and adapted to be broughtfor testing into connection with any contactpiece j at its board. Theother side of each test receiving instrument is connected to said commonWire of the lines in which is the rheotome. The connection of the testreceiving instruments to said common wire must be on the other side ofthe rheotome from that to l which the lines are normally connected.

B B are test-batteries. There should be a test-battery in the circuitbetween the place where the lines are united with said common wire andany test-plug. The battery may be in Fig. 4, l is the telephone-switch.

lrangement. Eare substantially as shown.. 'branch of the line connectsWith the frame from the common wire. In that case only one battery wouldbe required for the exchange. The common wire in which is the rheotomeis marked Wire c, and it extends, insulated from the lines, to eachsubscribers station, and is connected to each station apparatus, as willhereinafter be described. L

In the operators cord system shown in Fig. 3 D D are two loop-plugs, thetwo contactpoints of which are connected by double iiexible cords totheir loop-switch, clearing-out annunciator, and the operators telephoneand callin g-generator, substantially as shown.

One of the contact-pieces of each of the loopswitch plugs is connectedbya flexible conductorto a lever of the looping-in switch, and the twoother contact-pieces of the plugs are connected together by means of aiieXible cord-circuit. One pair of the plug-bolts are connected togetherthrough a clearing-out annunciator. Another pair are connected togetherthrough the operators telephone, and the third pair are connectedtogether through the calling generator or battery. Only one pair ofplugs with their cords and apparatus is shown, but other pairs may beadded in a Way which will beapparent to those skilled in the art. Thisapparatus is not more speciiically described, as its nature is quiteimmaterial as long as it properly performs the functions of connectingthe lines. The essential feature is that when a line is switched for usethe rheotome shall be cut oif from the line.

In the subscribers-station apparatus shown 2 is the calling-generator. 3is the signal-receiving `bell, and -i is 'the subscribers telephone.These parts may be the usual forms of apparatus and are connected asshown, or in other ways, so as to produce the required results. and isas shown. variations in the strength of a test-current The generator,however, is modified The modification consists, essentially, in

l the number and arrangement of the contactpoints of the automaticdevice. vmatic device shown is a modification of a The autoforrn verygenerally used. In consists in a V-shaped attachment to the hub of thedriv- 5 ing-wheel, a pin in the shaft, which engages -in this V-shapedarrangement, and a spring which presses against the .Wheel and bringsthe pin normally in the center of the V ar- The contact-points andcircuits One side or of the generator, as does also one end of thearmature-coil and the spring o of the automatic device. the lineconnects to the insulated spring o', l which bears on an insulated pieceon the arj mature-shaft to which the other end of the armature-coil isconnected. The contact- The other side or branch of IOO IIO

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b y ayo hesubscl rbersustation. Should, however, the line be switched atany board, this circuit is open, and the instrument will not sound orrespond. When the instrument on a test being made does not respond, theoperator knows, therefore, that the line is switched for use, and shewill not then connect it with another line.

The test receiving,` instruments and the battery should be such thatWhen closed to the circuits with the rheotoine the instrument Willrespond to the vibrations of the rheotoine. The parts should, however,be so related to the line-annunciators that on a test of a line beingmade it will not operate the annunciators. For this purpose theannuneiators may be such as will be operated only when one 1s switchedfor use, a common ungrounded" return-conductor, and test outfits inparallel, one at each board adapted to be applied to the test-contactsat their boards for testing; in combination with a eall-eireuitincluding said common return-conductor, one of said line conductors, andsaid normally closed pairs of contacts, including also an annunciatorand call-generator.

In witness whereof I hereunto subscribe my name this 29th day ofNovember, 1880.

MIL() G. KELLOG G,

Witnesses:

EMIL ABENI-IEIM, h/[ARGARETHA RIEHL,

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